Bicycle Mechanics - Newbie pump question

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froody
02-23-04, 04:00 PM
Little background:
I used to ride a beater mountain bike around town. Now I have a new road bike and am trying to inflate the tires. So I've got my nice pump and pump it up to 100 psi. And I can't get the pump off the tire! I worked it off a little bit, but it's not gonig any further. There's gotta be something simple that I'm missing. I feel pretty stupid sitting here with a bike in my room with a pump attached.

Here's some pics:
http://www.casualhacker.net/tmp/img_2896.jpg
http://www.casualhacker.net/tmp/img_2897.jpg
http://www.casualhacker.net/tmp/img_2898.jpg

The pump is a Serfas FP 100. The lock thing is definitely in the unlocked position.
Let me know if you need to know anything else.

Thanks,
Tim

Stubacca
02-23-04, 04:05 PM
You're positive the thumb lock is unlocked? I've never seen a floor pump that locks with the thumb lock down.
froody
02-23-04, 04:08 PM
To make extra double sure I just tried again, in both positions. It won't budge. I'm just pulling the pump head straight out. Do I have that part right at least?

Thanks,
Tim

PS
How much force am I supposed to be using? I'm pulling maybe a little bit harder than on a tight quick release lever.

Stubacca
02-23-04, 04:16 PM
Yep, you should always pull the pump head straight off the valve. If you pull at an angle or twist you risk damaging the tube at the bottom of the valve stem.

Sorry I can't offer any real help... not familiar with that pump at all.
froody
02-23-04, 04:25 PM
So you would just unlock it (which you expect to be straight out), and the pull the head straight out?
I'm thinking maybe the screw part of the valve is stuck in the pump head somehow. Bleh...
Thanks for replying.

Tim
georgesnatcher
02-23-04, 04:53 PM
That looks like a dual head pump. Is it possible you forced a schraeder valve into the presta head? If thats what happened you will have to muscle it off. :(
froody
02-23-04, 04:53 PM
So out of desperation I brought the wheel and pump to the bike shop here. Predictably, the pump came right off. I then pumped it up again, and once again the pump came right off. I guess this is just one of those things.

Tim
froody
02-23-04, 04:55 PM
George,
No, I definitely used the right hole.

Thanks,
Tim
slvoid
02-25-04, 09:53 PM
On my pump, you lift the tab to lock it to the valve, then lower it back down (like in the first picture) to unlock it. However, the plastic ring around the nozzle is like a screw. When you lift the tab, a cam compresses a piece of rubber so that its diameter gets smaller and grips the valve. But if when you lift it it still doesn't grip, you can adjust the pre-tension on the piece of rubber by turning that ring so that the final locked diameter of the nozzle is a bit smaller.
It could be that the thing was adjusted so that the diameter was the "locked" diameter before you even engaged it.